Noncorrosive alcoholic solution



Patented Aug. 5, 1 930 UNITED STATES PATIENT OFFICE WILLIAM S. CALCOTT,OFI'ENNS GROVE, NEW JERSEY AND HERBERT W. .WALKER, OF WILMINGTON,DELAWARE, ASSIGNORS T El I. DU PONT DE N EMOURS & COMPANY, OFWILMINGTON, DELAWARE, A CORPORATION OF DELAWARE N ON COBROSIVE ALCOHOLICSOLUTION No Drawing.

This invention relates to aqueous alcoholic solutions which aresubstantially inert with respect to iron. More particularly, it pertainsto the use of aldehyde-amine condensationproducts as a class ofcompounds which act as inhibitors for iron corrosion by aqueoussolutions of monoand polyhydric alcohols.

As is Well known, water solutions of these alcohols attack metallic ironin the form. of free metal, steel and cast iron, very rapidly underordinary conditions and considerable corrosion, as indicated by spots ofrust, iron oxide deposits and sediment, takes place.

We have found that if a small quantity of an aldehyde-amine condensationproduct be dissolved in a monohydric alcohol such vas ethyl alcohol orin a polyhydric alcohol such as glycerine or ethylene glycol and thealcohol then diluted to any desired concentration with water thereresults a mixture which does not corrode iron to the extent that it isrusted in an alcohol solution of the same concentration not so treated.A distinct protective action on iron is observed in alcohol solutionstreated with these aldehyde-amine condensation products after heatingseveral days at 8'590 C. T healdehyde-amine condensation productswhichthus decrease very appreci-" ably the rate of corrosion of iron inmonoand olyhydric alcohol solutions are those formed y, condensingaldehydes with ammonia or aliphatic or aromatic primary, secondary orsubstituted amines.

For example, if the butylaldehyde-aniline condensation product, molarratio of 2: 1, be dissolved in ethyl alcohol, lycerine, or ethyleneglycol to the extent 0 0.1% of the final solution and water added to thealcohol to make a 40% ethyl alcohol, glycerine or glycol solution, thereresults a mixture which is less solution. The above molar ratio is givenonly I above example, which is as an example and it is not our intentionto be limited thereto as it may be varied within desirable limits.- I

The particular substancesemployed in the resented only by wayof'illustration may, 0 course, be substituted by other compounds ofsimilar constitution. Thus, for the butylaldehyde we may Applicationfiled'October 5,1928. Serial No. 310,672.

substitue formaldehyde, acetaldehyde, benzaldehyde, furfuraldehyde,aldol, etc., andin place of aniline, monoor diethyl aniline,

o-toluidine, p-toluidine, aor b-naphthyl-.

amine, benzidine, n-butylamine, n-dibutylamine, ethanol amines, etc.maybe used.

Moreover, products containingcarbon disulfi'de in combination 'with thealdehydeamine combination may likewise be a'dvantageou sly employed.

The protective action of the described aldehyde-amine combinations isretained in hot alcoholic solutions as well as those kept at singly orin combination or may be employed together with other agents inpreparing noncorrosive alcoholic solutions. They may also be employed toinhibit corrosion by a mixture of alcohols.

As many difierent combinations of the general type herein disclosed maybe employed' and are within the scope of the invention, it is not ourintention to be limited except as indicated by the appended claims. Weclaim :4

1. The process of inhibiting the corrosion of an oxidizable me'tal uponcontact with an aqueous alcoholic solution which comprises contactingsaid solution. with the oxidizable metalin the presence of analdehyde-amine condensation product. 2. The process of inhibiting thecorrosion of iron 'upon contact with an aqueous alcoholic solution whichcomprises contacting said corroslve to 1ron than an untreated alcohol--solution with the iron in the presence of a product resulting from thecondensation of an I aldehyde with an amine 3. The process of inhibitingthe corrosion product resulting from the condensation of an aldehydewith-an amine of the group consisting of anilirte, mono=ethyl-aniline,,-di

ethyl aniline,o-toluidine,p-toluidine, ana haniline, diethyl aniline,o-toluidine,

thylamine, b-naphthylamine, benzidine, nutylamine, n-dibutylamine andthe ethanol amines.

4. The process of inhibiting the corrosion of iron upon contact With anaqueous alcoholic solution which comprises contactin said solution withthe iron in the presence 0 a product resulting from the condensation ofan aldehyde oi the group consisting of butylaldehyde, formaldehyde,acetaldehyde, benzaldehyde, turt'uraldehyde and aldol with an amine.

'5. lfhe process of inhibiting the corrosion of iron upon contact withan aqueous alcoholic solution which comprises contacting said solutionwith the iron in the presence of a product resulting from thecondensation of analdehyde of the group consisting of butylaldehyde,tormaldeh de, acetaldehyde, benzaldehyde, furfural ehyde and aldol withan amine of the group consisting of aniline, mono-ethyl-aniline, diethylaniline, o-toluidine, p-toluidine, a-naphthylamine, b-na hthylarnine.benzidine, n-butylamine, n-di utylamine and the ethanol amines.

6. The process of inhibiting the corrosion of iron upon contact with anaqueous alcoholic solution which com rises contacting said solution'withthe iron in the presence of butylaldehyde-aniline.

7.. The process of inhibiting the corrosion of iron'upon contact with anaqueous alcoholic solution which comprises contacting said solution withthe iron in the presence of an aldehyde-amine carbon disulfidecondensation product.

8. A mixture substantially non-corrosive towardiron and comprising anaqueous solution of an alcohol and an aldehyde-amine.

I 9. A mixture substantially non-corrosive toward iron and comprising anaqueous solution of an alcohol and a product resulting from thecondensation of an aldehyde of the roup consistin of butylaldehyde,formaldehyde, acetaldehyde, benzaldehyde, furfuraldehyde and aldol Withan amine of the group consisting of aniline, mono-ethyl- -toluib-na hthyamine,

dine, a-naphthylamine,

nibutylamine benzidine, n-butylamine, and the ethanol amines.

10. A mixture substantially non-corrosive tion of an alcohol and theproduct resulting from the condensation of an aliphatic aldehyde with aprimary aromatic amine.

12. A mixture substantially non-corrosive toward iron and comprising anaqueous solu- In testimony whereof We afix our signatures.

WVILLIAM S. CALCOTT.

HERBERT W. WALKER.

